Thermostatic controlling device



April 1941- N. ERLAND AF KLEEN 2,238,043

THIRIOSTATIC CONTROLLING DEVICE Original Filed Jan. 20, 1938 ATmRNEm Patented Apr. 1-5, T941 THERMOSTATIQ CONTROIJJNG DEVICE Nils Erland at Kleen, Stockholm, Sweden riglnal application January 20, 1938. Serial No.

185,978. Divided and this application October 16, 1939, Serial No. 299,774. In GreatBritain January 22, 1987 1 Claim.

i invention relates to a snap action thermostatic controlling device more particularly intended for controlling the operation of refrigerating systems of the kind employing one or more intermittently operating units, each unit compris ing a generator-absorber, a condenser and an evaporator. p

In the operation of systems of this kind, it is necessary to operate a heat-controlling switch at a definite point in the cycle of Operations and for this purpose a thermostatic controlling device is required which will operate suddenly at a predetermined-temperature level. As the temperature in the boiler-absorber rises and falls regularly and the temperature range is considerable a considerable amount of energy is available to a thermostatlc device having a bulb located in the boilenabsorber.

l s application is a division of my application wrial No. 185,978, iiled Jan. 20, 193B.

The object of the present invention is to provide an improved thermostatic device capable of making use or substantially the whole of the energy available as aforesaid tor effecting the required switching operation suddenly when a predetermined level of temperature has been reached.

The invention consists in a snap action thermostatic controlling device comprising a movable part, a temperature responsive expansible part, a spring for transmitting the movement of said exnsible part to said movable part, a detent for holding said movable part and means operative by said eitpansiblepart to actuate said detent to release said movable part at a predetermined temperature.

'Ihe invention will now be described with reference to the accompanying drawing in which Figures 1 and 2 are diagrammatic illustrations of a snap action mechanism for the thermostatic control.

The mechanism comprises an actuating spring I00 adapted to be gradually loaded by the action of a bellows device I00 and a detent I00 adapted to release the spring so as to bring about a sudden actuation of the switching mechanism when the'temperature oi the thermostat reaches a predetermined value.

The spring I00 takes the form of a springy plate fixed at one end to a block I03, mounted so that it on suitable fixed supports. The bellows I00 tends to rock the block I00 and plate I00 to the left as seen in the drawing and a control spring I0! is arrangedto act in opposition to the bellows.

is free to rotate on aspindle I02 mounted The upper end of the springy plate I04 engages in a recess formed in a drum I00 fixed to a rockshaft IOI supported in suitable bearings (not shown) fixed abovethe spindle I02, the arrangement being such that the pressure or the bellows- I06 acting through the plate it tends to rotate the drum I00 in the clockwise direction as seen in Figure 6.

The detent I08, which is controlled by a spring I00, is arranged to engage a ratchet tooth or like projection IIO on the drum I00 so as to hold the drum against rotation in the clockwise direction.

A rigid lever I I I fixed to the block I00 is arranged to engage and move the detent I00 sons to disengage the same from the tooth IIO when the temperature of the thermostat connected to the bellows I06 reaches a predetermined limit. As the bellows I05 expands with rising temperature, the springy plate I04 is gradually loaded. At the same time the detent I00 is gradually displaced by the action or the lever I I I. when the set temperature is reached, the detent I00 clears the tooth H0 and the drum I00 and rock shaft IOI then receive a sudden partial rotation in the clockwise direction under the action of the spring Ill.

A detent I00a similar to the detent I00 is arranged to lockthe drum I00 in its new position by engagement with a tooth IIOa similar to the.

case, as the bellows I00 contracts with falling temperature the pressure of the control spring II! will tend to impart anti-clockwise rotation to the drum I00 through the medium of the plate I00. As the temperature continues to fall, the springy pistol is gradually loaded and the detent I00a is gradually displaced. At a predetermined temperature, the detent Illa clears the tooth 0a and the drum I00 and shaft III are then suddenly restored to the position shown in the drawing under the action of the springy plate I00. p

In the case of a two-unit refrigerating system in which two thermostats are employed, one of the thermostats is connected to the bellows I00 and the other is connected to a second bellows I00a. (see Figure 2) A separate block Illa. spring plate Iota and control spring Illa are provided in connection with the bellows I000. these parts being similar to the parts I 00, Ill and Ill previously described, but being arranged to work in the opposite direction so that the expansion of the bellows 106a tends to rotate the drum H00 in the anti-clockwise direction. In this case, the lever Illa is fixed to the block 803a so that the release of the detent l08a will be effected by the expansion of the bellows lflia and will occur when the temperature of the thermostat connected to the bellows 106a reaches a preset limit. In Figure 7 01' the drawing, the parts I08, I01, B03 and III are omitted in order to permit the parts Mia and Ma to be seen.

It will be appreciated that the movements of between two operating positions, movable latch means adjacent each side of said member and cooperating therewith to hold said member in each of its operating positions, rockable means, leaf spring means secured at one end to said rockable means and operatively connected at the other end n to said rocklngmember for moving the latter althe rock shaft H can be utilized for actuating a roc'k burner for delivering a heat supply to either of two boiler-absorbers or for operating any gas valve mechanism or electrical switch mechanism for effecting the required change over.

I claim:

A thermostat snap-switch device of the class described, comprising a rocking member shiftable ternately to its two operating positions, temperatare-responsive elements movable from retracted positions to extended positions for rocking said rockable means alternately in opposite directions to correspondingly load said spring means, and separate means on said rockable means operable by said temperature-responsive elements and cooperating with said latch means to release the latter when the respective temperature-responsive element reaches its extended position, whereby said leaf spring means quickly shifts said rocking member from one operating position to the other.

NILS ERLAND AF KLEEN. 

